The present disclosure relates to display systems. In particular, the present disclosure relates to a device and method for configuring a data bus width between a microcontrol unit (MCU) and a display device.
Display systems generally include display devices and MCUs for driving the display devices. Display systems are widely used in portable electronic mobile phones, MP3 players, digital cameras, and so on.
FIG. 1 is a block diagram of a general display device. Referring to FIG. 1, the display system 10 includes a display device 11 and an MCU 18. The display device 10 and the MCU 18 exchange data with each other through a data bus 19.
The display device 11 includes an LCD panel 12 and an LCD driver IC 14. The LCD driver IC 14 is formed in a single semiconductor chip. The LCD driver IC 14 provides a drive signal to the LCD panel 12 by way of signal lines 15. The MCU 18 provides a control signal CTRL and data to the display device 11. The MCU 18 controls the display device 11, enabling an image to be output as a picture.
Continuing on in FIG. 1, the display device 11 has mode set pins MODE for setting an operation mode. The mode set pins MODE are connected to a power source voltage or a ground voltage on a printed circuit board (PCB) (not shown). The mode set pins MODE, as external pins in general, are fixed on the PCB. The mode set pins MODE, however, need not be always fixed to a PCB, being supplied with a mode signal from the MCU 18.
The MCU 18 has a variable interface mode in accordance with its type. For instance, the MCU 18 may have the 68-series interface mode of Motorola, or an 80-series interface mode of Intel. Further, even in MCUs made by the same manufacturer, they may be designed so that each has a different data bus width. For example, Intel's 80-series CPU has a data bus width of 8, 9, 16, or 18 bits.
The display device 11 is required to set an operation mode in accordance with an interface mode of the MCU 18 by using the mode set pins MODE before communication, for example, at the first system reset time. For example, the display device 11 sets an operation mode through the mode set pins MODE, whether the MCU 18 is Motorola's 68-series interface mode or Intel's 80-series interface mode.
As such, the easiest way for setting an operation mode of the display system 10 is to use the mode set pins MODE. If there is an increase of a data bus width and interface mode of the MCU 18, however, the number of mode set pins MODE also increases.
Increasing the mode set pins in number for various operation modes, however, makes a systemic burden heavier in operation. Namely, increasing the number of the mode set pins, extends the whole area occupied by all signal lines in the display system. As it is necessary to change a set value of an operation mode by the MCU 18, a hardware structure must be modified. Further, from an increase in the number of the mode set pins MODE, it also complicates a PCB pattern for fixing the mode set pins on a PCB. Thus, there is a problem of fabricating a new PCB pattern in such case.